The oxidative degradation of ethylene/vinyl alcohol copolymers

The oxidative behavior of ethylene/vinyl alcohol copolymers has been examined after initiation by γ-irradiation. Oxidation products were identified and quantified by infrared spectroscopy after the use of selective derivatization reactions which allowed the resolution of the various alcohol, hydroperoxide and carbonyl species produced. Extensive preferential attack at the sites was observed to give backbone ketone and probably hydrogen peroxide. The latter was not unambiguously identified or quantified because of its volatility. The derivatization techniques failed at vinyl alcohol levels above 20 wt%, probably because of the low gas permeability of these films. Implications of the observed products to the oxidation of polyethylene are discussed.